Drive device provided for operating adjusting devices in motor vehicles

ABSTRACT

A drive device provided for operating adjusting devices in motor vehicles includes an axial-field motor equipped with rotor discs. A gear mechanism is connected to the motor shaft and to a drive element of the adjusting device. The motor shaft is supported on the periphery of the axial-field motor by radial webs that are part of a supporting element. A bearing bush for accommodating the motor shaft is integrated inside the body of the supporting element.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a National Phase Patent Application of InternationalApplication Number PCT/DE2003/003735, filed on Nov. 6, 2003, whichclaims priority of German Patent Application Number 102 53 071.8, filedon Nov. 7, 2002.

BACKGROUND

The invention relates to a drive device for adjusting devices in motorvehicles.

From the International Patent Application No. PCT/EP00/01093(Publication No. WO 00/48294) an electric machine is known designed asan axial field motor or generator and having a rotor mounted rotatablein a housing and a rotor shaft which extends out from the housing. Anumber of electromagnet structural elements are mounted locally fixed inthe housing spaced out at regular angular spaces from the rotationalaxis of the rotor shaft and each having a coil core supporting a coilwinding of one or more wires. The pole faces of the end sides of thecoil cores are aligned towards the pole faces of permanent magnets whichare mounted rotationally secured in or on the rotor and which each havean opposite polarity circumferentially in succession. The coil cores ofthe electromagnet structural elements are arranged parallel to the axisof rotation of the rotor shaft inside the housing so that their oppositeend sides each lie in two planes spaced from each other and running atright angles to the rotational axis of the rotor shafts.

The connection between the disc-shaped rotors and the rotor shaft andtheir bearing in the housing of the electric machine means that fortesting and actuation the rotors and the stator have to be arranged ormounted completely in the housing. The support and bearing of the rotorshaft on two housing sides however requires an exact precision betweenthe distance of the support points on the housing and the verticalstructure of the stator and disc-shaped rotors since owing to the axialsupport of the rotor shaft there is the risk of over specifying thebearing and consequently high friction losses.

A further problem exists in observing the two very important air gaps inrespect of the rotor discs. This coordination requires accuratemeasuring for example by using close-fitting discs if several parts arearranged between the rotor discs whose tolerances have to be taken intoconsideration.

SUMMARY

The object of the invention is to provide a drive device of an axialfield motor and a gear mechanism in which the axial field motor can alsofunction without the motor housing and can be pre-checked for its mainproperties, wherein its construction avoids over specifying and thushigh friction losses or expensive dimensioning, requires no precisionmeasuring to observe the air gaps relative to the rotor discs and whichenables a connection with a self-locking or non-self locking gearing,and which allows a flat space-saving method of construction.

The solution according to the invention provides an axial field motorwhich can also run without a motor housing and can thus be pre-checkedfor its essential properties and whose structural design eliminatesover-specifying and thus high friction losses or an expensiveoversizing. Since the radial forces which stem from the motor shaft areintroduced into the housing of the drive device or axial field motorthrough axially extending positive locking regions of radial webs, noparts are required in the axial direction with their tolerances formounting the motor shaft so that there is no need for measuring withthin close fitting discs or the like. Observing the air gaps depends byway of example only on coordinating the motor shaft and a bearing bushsupported on the periphery of the axial field motor to hold the motorshaft. The method of constructing the axial field motor enables aconnection with different geometrical shapes and by incorporatingself-locking properties into the axial field motor also a connectionwith self-locking or non-self locking gear mechanisms.

The integration of the motor shaft into the axial field motor alsoenables an extremely flat structure as well as by connecting the gearmechanism to the axial field motor a very compact structural form ofdrive device.

The design according to the invention for mounting the motor shaftproduces with its support on the peripheral side with webs pointing likerays towards the centre of the axial field motor a virtual motor axle sothat no axial support of the motor shaft is required and thus no part isplayed by the vertical structure of the function parts of the axialfield motor. This not only eliminates the risk of over-specifying whichleads to considerable friction losses or very high accuracy demands withvery narrow tolerances, but the axial field motor is also fullyfunctional without a housing and can therefore be pre-tested andadjusted in this state.

The radial webs are preferably supported on the periphery of the axialfield motor and have radially directed end ribs which are connectable inthe axial direction to the housing of the axial field motor or the drivedevice in that they engage preferably in positive locking elements ofthe housing.

Furthermore axially extending positive locking regions of the radialwebs can engage in recesses in the housing.

In order to form the virtual axle and support of the motor shaft on theperiphery of the axial field motor the radial webs are designed as partof a support element and protrude from a base body holding the motorshaft. Through this configuration of the motor shaft bearing the supportbody can be inserted into a drive housing through the circumferentiallyspread out radially aligned end ribs which protrude from the base bodyof the support element whereby the functional capacity of the axialfield motor does not however depend on the connection with a drivehousing.

A bearing bush integrated in the base body of the support element forholding the motor shaft can either be formed as part of the base body ofthe support element or can be inserted in a corresponding socket of thebase body of the support element. In the second variation afree-standing external collar of the bearing bush adjoining an end faceof the support element serves to fix the position of the bearing bushinside the support element.

The support element is preferably part of the stator of the axial fieldmotor, i.e. by integrating electromagnetic structural elements into thesupport element it widens the function of the support element beyond astatic function so that both the number of parts and also themanufacturing costs are reduced.

The connection of the support element and thus stator to a housing ofthe axial field motor or a housing which accommodates both the axialfield motor and the gear mechanism of the drive device is provided bythe radially aligned end ribs of the radial webs which are preferablysupported elastically on the housing of the axial field motor or drivedevice. Between the radially aligned end ribs and the housing of theaxial field motor or drive device it is possible to mount a ring whichis elastic at least in the axial direction to take up the tolerances ofthe two housing halves of a two-part housing and to enable an axiallyplay-free mounting.

In order to form the axial field motor the motor shaft is connected toat least one rotor disc which is mounted on an end face of the statorwhilst the other end face of the stator forms a magnetic short-circuit.The motor shaft is however preferably connected to rotor discs which aremounted on both end faces of the stator and on which are mountedpermanent magnets which face the stator and have circumferentiallyalternating polarity.

On the output side the motor shaft is connected to a pinion of the gearmechanism formed as a spur wheel gear of the drive device. The spurwheel gear has a toothed wheel of a first gear stage meshing with thepinion and connected coaxially to a second pinion pf a second gear stagewhich meshes with a second gear wheel connected to the drive element ofthe adjusting device.

The drive device is preferably mounted in a twin-shelled housing whoseone housing shell is connected through the elastic ring to the radiallydirected end ribs of the support element. The housing shell having theelastic ring furthermore has fixings through which the drive device canbe connected to a holding device.

Overall the drive device according to the invention is characterised asa result of the special structural features of the axial field motorthrough a simple assembly which permits large tolerances of theindividual component parts, in which no consideration has to be made fora possible tensioning of the axial field motor. In addition to the lowfriction losses which result the drive device is characterised by theabsence of any troublesome noises.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in further detail with reference toan embodiment illustrated in the drawings.

FIG. 1 is a longitudinal sectional view through the drive deviceaccording to the invention with an axial field motor and a spur wheelgear.

FIG. 2 is an exploded view of the axial field motor with a stator, tworotor discs, a bearing bush for holding the motor shaft and a coilspring brake.

FIG. 3 is a diagrammatic perspective view of the support element with acoil body which is to be used.

FIG. 4 is a diagrammatic perspective view of the support element in analternative embodiment with axially aligned positive locking elementsand a diagrammatically illustrated counter positive locking element onthe housing side.

FIG. 5 is a plan view of the support element.

FIG. 6 is a first perspective view of the drive device with axial fieldmotor and spur wheel gear and a cable winding roller of a cable windowlifter.

FIG. 7 is a further perspective view of the drive device with axialfield motor and spur wheel gear and a cable winding roller of a cablewindow lifter.

FIG. 8 is a plan view of the drive device according to FIGS. 6 and 7.

FIG. 9 is a perspective view of the housing of the drive device withaxial field motor and spur wheel gear contained therein.

DETAILED DESCRIPTION

FIG. 1 shows a longitudinal sectional view through a drive device for anadjusting device in a motor vehicle, by way of example for a cablewindow lifter for lifting and lowering a window pane in a motor vehicledoor. The drive device contains in a housing 9 which comprises twohousing shells 91, 92 an axial field motor 1 with stator 2 and rotordiscs 3, 3′ arranged on the two end sides of the stator 2, a gearmechanism 6 designed as a spur wheel gear, and a drive element of anadjusting device in the form of a cable winding roller 7. As can be seenfrom the sectional view according to FIG. 1, the drive device ischaracterised in particular by a flat method of construction which isconditioned through the structural shape of the axial field motor 1 aswell as by using a spur wheel gear 6 and the axially boxed constructionof the function elements of the drive device. Despite the structurewhich is kept to a minimum in the axial direction a tension-free designis ensured without over-specifying whose essential features will beexplained below.

The axial field motor 1 is comprised according to FIGS. 1 and 2 of astator 2 and two rotor discs 3, 3′ arranged on either side of the endfaces 27, 28 of the stator 2. The one rotor disc 3 is connected to apinion 61 which forms the output of the axial field motor 1 and input ofthe spur wheel gear 6. The rotor discs 3, 3′ are connected to a motorshaft 5 which is mounted in a bearing bush 4 which is supported notaxially but through a star-shaped support element 20 which forms at thesame time the mechanical base body of the stator 2 of the axial fieldmotor 1.

As can be seen from the perspective views of FIGS. 3 and 4 as well asthe plan view according to FIG. 5, the support element 20 consists of abase body 21 from which a number of webs 22 protrude radially andbetween which inserts 23 are formed for holding the coil bodies 25 whicheach form, through alternating pairs of winding connections, two northpoles and two south poles so that each two north poles follow two southpoles. The base body 21 has in the center a cylindrical opening or bore24 which is formed either as a bearing bush for holding the motor shaft5 or can be mounted onto the one bearing bush 4 according to FIGS. 1 and2 in which the motor shaft 5 is mounted. For this the bearing bush 4 hasa free-standing outer collar 40 which bears against the one end side 27of the support element 20 and thus fixes the position of the bearingbush 4.

The radial webs 22 have at their outer ends radially directed positivelocking elements in the form of radially directed end ribs 22 a whichpreferably engage through an elastic ring 10—as will be explained withreference to FIGS. 6 and 7—in positive locking regions of the housing 9of the axial field motor or drive device.

Furthermore axially directed positive locking elements are provided inthe form of projections 22 b and webs 22 c which extend over the lengthof the radial webs 22 and together with the radially directed end ribs22 a introduce the radial forces stemming from the motor shaft 5 intothe housing 9.

The counter positive locking elements of the housing 9 are designedaccordingly as recesses and take up the motor forces through their stopfaces.

Whilst the axially directed projections 22 b engage in correspondingrecesses in a housing base, the webs 22 c are assigned correspondingrecesses 95 in the base contour of the housing 9 whose ends arepreferably closed for radially guiding the support element 20.

The rotor discs 3, 3′ stand opposite the end sides 27, 28 of the supportelement 20 whilst forming slight air gaps and have permanent magnets 30,30′ with circumferentially changing polarity which form the magneticshort-circuit for the magnetic field of the coils of the stator 2.

As can be seen in particular from the sectional view in FIG. 1, themotor shaft 5 is supported solely through the bearing bush 4 and thesupport element 20 on the periphery of the drive device, i.e. there isno axial support of the motor shaft 5 relative to the housing 9, butonly a support over the periphery of the housing 9.

The axial field motor 1 is thus a functioning part independent of thehousing 9 of the drive device and whose functions can be tested withoutthe housing 9 and even without the gear mechanism and whose functionparts can be corrected or exchanged where applicable. The connection ofthe axial field motor 1 with the housing 9 of the drive device isthrough an elastic ring 10 which is fitted according to FIG. 6 on theradially aligned end ribs 22 a of the radial webs 22 of the supportelement 20 and which is supported according to FIG. 1 on the one housingshell 91 of the twin shell housing 9. Through the elastic ring 10 it ispossible to compensate tolerances arising in the axial direction in theaxial structure of the axial field motor 1 and in the dimensioning ofthe housing 9 of the drive device and thus to ensure a tension-freefitting taking into account greater tolerances.

In order to avoid counter-effects on the part of the adjusting devicedriven by the drive device, i.e. to prevent unintended adjustment of theadjusting device in the event of an adjusting torque which is greaterthan the drive torque of the drive device a brake device is providedwhich ensures a self-locking of the drive device in the event of atorque of the adjusting device which exceeds the drive torque of thedrive device. For this purpose and to provide the flattest possibledrive device the double axial field motor shown in FIG. 2 has a brakedevice in the form of a coil spring brake with a coil spring 8 which ismounted between the rotor disc 3 and a pinion 61 on a gear mechanismprovided on the output side and connected to the rotor disc 3 and whichbears with pretension against the outside wall of the fixed bearing bush4 in which the motor shaft 5 is rotatably mounted.

The actuation of the coil spring 8 is through its radially outwardlyprotruding spring ends which are radially opposite one another. In therest state or in the current-less state with the onset of torqueintroduced from the output side the coil spring 8 is actuated by thepinion 61 in both rotational directions through one of its spring endsso that it is firmly clamped at the outer edge of the bearing bush 4.For this according to the perspective view in FIG. 2 projections orshift claws 610 project down from the pinion 61 to each interact withone of the spring ends of the coil spring 8. With the presence of torqueon the output side the coil spring brake is hereby locked and arotational movement is prevented as a result of the clamping action.

The shift claws 610 of the pinion 61 act in the event of torque on theoutput side for locking the coil spring brake on the ends of the coilspring 12 in order to contract the latter, thus to clamp against theoutside wall of the bearing bush 10.

Each of the two spring ends of the coil spring 8 is furthermore assigneda shift region of the rotor disc 3 which releases the coil spring brake,i.e. disengages the coil spring 8 when the axial field motor 2 isenergized. The one or other shift region acts on the associated springend of the coil spring 8 in both rotational directions of the rotor disc3 in order to lift the spring so far away from the outside wall of thebearing bush 4 that it no longer counteracts the rotational movement andonly the smallest possible efficiency losses occur during operation ofthe axial field motor 2.

Further details for the design and functioning of the coil spring brakecan be concluded from the German Patent Application No. 102 36 372.2 towhose contents reference is made.

The gear mechanism of the drive device consists according to FIGS. 1 and6 to 8 of a spur wheel gear 6 whose first gear stage contains the pinion61 which is connected to the motor shaft 5 and meshes with a gear wheel62 mounted on an axis 65. The pinion 63 of a second gear stage of thespur wheel gear 6 which is mounted coaxial with the gear wheel 62 mesheswith a gear wheel 64 which rotates about an axis 66 of the second gearstage and which in turn is coupled to the drive element 7 of theadjusting device which is driven by the drive device and in thisembodiment consists of a cable winding roller 7 for a cable windowlifter.

FIGS. 6 and 7 show the different perspective views of the axial fieldmotor and spur wheel gear mechanism. FIG. 8 shows a plan view of thefunction parts of the drive device contained in the housing 9 wherebythis plan view shows the support of the motor shaft 5 on the peripheralside.

FIG. 9 shows in a perspective view the housing 9 which encloses thedrive device and which is comprised of two housing shells 91, 92 asdescribed above. The drive device can be electrically connected to apower supply and/or a control or regulating device through a plugconnection 93 whilst the mechanical connection between the drive deviceand holding device is through fixing elements 94 which are mounted onthe one housing shell 91.

1. A drive device for adjusting devices in motor vehicles, comprising anaxial field motor having a motor shaft and a gear mechanism which isconnected to the motor shaft and with a drive element of the adjustingdevice, wherein radial forces stemming from the motor shaft areintroduced into a housing of one of the drive device and the axial fieldmotor through axially extending positive locking regions of radial webs.2. The drive device according to claim 1, wherein the radial webs aresupported on the periphery of the axial field motor.
 3. The drive deviceaccording to claim 1, wherein the axially extending positive lockingregions comprise radially aligned end ribs of the webs which engage inpositive locking elements of the housing.
 4. The drive device accordingto claim 3, wherein the radially aligned end ribs of the webs areconnected with the housing in the axial direction.
 5. The drive deviceaccording to claim 1 or 2, wherein the axially extending positivelocking regions of the radial webs engage in recesses of the housing. 6.The drive device according to claim 3, wherein the radial webs are partof a support element and protrude radially from a base body holding themotor shaft.
 7. The drive device according to claim 6, wherein a bearingbush for holding the motor shaft is integrated in the base body of thesupport element.
 8. The drive device according to claim 7, wherein thebearing bush is a part of the base body of the support element.
 9. Thedrive device according to claim 7, wherein the bearing bush is insertedin one of a central opening and bore of the base body of the supportelement.
 10. The drive device according to claim 9, wherein a freestanding outer collar of the bearing bush adjoins an end face of thesupport element.
 11. The drive device according to claim 1, wherein thesupport element is a part of the stator of the axial field motor. 12.The drive device according to claim 6, wherein a ring which is elasticat least in the axial direction is mounted between the radially alignedend ribs of the webs of the support element and the housing.
 13. Thedrive device according to claim 1, wherein the motor shaft is connectedto rotor discs which are mounted on two end faces of the stator.
 14. Thedrive device according to claim 1, wherein the motor shaft is connectedto a pinion of the gear mechanism which is designed as a spur wheelgear.
 15. The drive device according to claim 14, wherein the spur wheelgear has a gear wheel of a first gear stage meshing with the pinion andconnected coaxially to a second pinion of a second gear stage whichmeshes with a second gear wheel which is connected to the drive elementof the adjusting device.
 16. The drive device according to claim 12,wherein the housing comprises a twin-shell housing whose one housingshell is connected through the elastic ring to the radially directed endribs of the radial webs of the support element.
 17. The drive deviceaccording to claim 16, wherein the twin-shell housing holding theelastic ring has fixings through which the drive device is connectableto a holding device.
 18. An adjusting device in motor vehicles,comprising: a drive element, a drive device comprising an axial fieldmotor having a motor shaft and a gear mechanism which is connected tothe motor shaft and with a drive element of the adjusting device,wherein radial forces stemming from the motor shaft are introduced intoa housing of one of the drive device and the axial field motor throughaxially extending positive locking regions of radial webs.